Thank you for all your posts. Please find below my answers or clarifications:
1. I understand where you could interpret this service as an extension of the tourist visa or card. But, these documents are issued by the Ministry of Foreign Affairs while your stay is authorized by the Immigration department. The first one allows you to legally enter the country while the other one allows you to stay in the country. It is better to separate the terms of visa, tourist card, extension of stay and overstay to better understand Immigrations goal;
2. While the tourist is allowed to legally stay in the country for a 60 day period according to Immigration's law, they can still charge you a penalty if you overstay past the 30-day mark because its the time allowed by the visa and tourist card. I understand if it is confusing and looks like a money grab. You can check if you will pay penalty by checking the entry stamp in your passport, where Immigration puts the days allowed. It says 'Entrada' and in a line, they put '60 días', for example. If you leave before that time is up and they still charge you, this is your legal base to argue with them;
3. It is not an extension for 6 months. Technically speaking, it's a 90-day extension plus your 60 days that equals 120. Once you make the request, the Immigration page won't allow you an exiting day past the 120 mark;
4. If you overstay past the 120 days mark, you will pay a penalty according to the chart. For example, if you enter today March, 13 and you get an approval to extend your stay until July 7th (the 120th day) but you leave the country on the 10th (the 124th day), you will pay an RD$2,500 penalty, the first one of the chart even if it says from 30-90 days. It will move to the next penalty of 4,000 if you stay past 90 days, etc...
5. This extension can only be done at the Immigration's site. At the airport you only pay penalties.
6. I understand the cost is between RD$2,500 for 60 days or $4,000 for 90 days.
7. This doesn't change the legality of the driver's license. Different institutions again.
8. Drak's example in his/her first post (excepting the part of the 6 months) is correct. And thank you!
My post referred to the law, my conversation with Immigration and posts made by them. Nevertheless, I cannot deny that as a new service there can be initial confusion. If any of you request it and obtain it, and leave the country accordingly, please post your experience here and I will change my post if necessary.
Kindly let me know if I left anything out.
